Structure and properties of NiAl-Cr(Co,Hf) alloys prepared by centrifugal SHS casting. Part 1 - Room temperature investigations

The structure and mechanical behavior of NiAl-based intermetallic alloys alloyed with Hf, Cr and Co at their total content (Cr+Co)=18 at% were studied. The alloys were prepared by centrifugal SHS casting from oxide raw materials. The mechanism of precipitation hardening is shown to take place at the Cr/Co ratios >0.5, leading to the formation of chromium-based inclusions and nanosized precipitates in the NiAl dendrite body. The resulting alloys have a three-level hierarchical structure with oxygen, nitrogen, and carbon impurity contents of 0.129, 0.0045, and 0.04 wt%, respectively, and the ultimate compressive strength at room temperature equal to 2300 MPa.